Are there any reasons why Vortex Method doesn't perturb the flow using SAS
 

I'm modelling flow past a surface mounted cube using the SAS model. Is there a reason why I can't see any inlet perturbations using the Vortex Method (N=1000) in the flow field upwind of the cube? I've run it for 100s and looks smooth as RANS. :confused::confused: I'm super confused. Any thoughts?